fix(legacy-plugin-chart-country-map): Correct ISO 3166-2 county codes…

… for Estonia (#1344)

I have no idea how this happened, but most Estonian county codes were
off by one.

Unfortunately I couldn't compare it to latest data from
naturalearthdata.com, since download links are currently down.

Source: https://en.wikipedia.org/wiki/ISO_3166-2:EE#Counties

Primary source: https://www.evs.ee/en/iso-3166-2-2020 (but I'm not going
to pay 100 €)